"Machinable" plastic

[montana_native]

Hello,

Can someone steer me in the direction of obtaining plastic for prototyping in a 4-axis CNC? I am looking for bars that are roughly 36"x6"x3" to run in the mill prior to using aluminum.

Thanks!

 

[avidflyer]

delrin cheap and turns like butter

 

[Tucker65]

I would venture to say that wood might be your best bet. Plastic bars that size might cost just as much, if not more than aluminum.

John

 

[Walt Krafft]

Machinable wax is made for that. MSC had smaller pieces. Cost could be an issue. I remember getting 12x3x4 pieces.

 

[liljoe]

Yep, aluminum might be cheaper than most plastic stuff.

Joe

 

[riflewoman]

https://www.plastiblocks.com/blocks

Hold on to your wallet....

 

[liljoe]

 

[Kevin Taylor]

Part of the appeal of machinable wax is if your programming crashes it is far less destructive on tooling and jigs. More to the cost than just material.

 

[magic mike]

MDF works great as long as you can keep up with the dust etc. HDPE if dust is an issue. Delrin will put you in the poor house.

 

[carlsbad]

aluminum may be cheaper.

 

[357Mag]

Montana -

Howdy ?

I’ve seen auto design houses use machining tools on clay.


With regards,
357Mag

 

[Walt Krafft]

MSC has machinable wax 5x3x10 $72

 

[Fast14riot]

I have no idea of the machinability of the material. But I wonder if a piece of composite lumber from home depot or something similar might work?

 

[Mechdraw]

Hi Montana
Acetal 'C' , one of the best machining engineering plastics available.
Cheers

 

[Dusty Stevens]

Ive never seen any cnc shop use anything but wax on prototyping. They call it machinable wax and comes in every shape you can imagine. The chips flow right so you can make a plan on managing waste too.

 

[Fast14riot]

Hi Montana
Acetal 'C' , one of the best machining engineering plastics available.
Cheers

Acetal Pom-c is also one of the most expensive plastics available. I sell 1" thick at $87/ft²

 

[montana_native]

I am learning that lower grade aluminum may be cheaper.... The "crashing" mentioned above is a concern too. I've also considered wood; which may be what I end up using. Thanks for all of the replies!

 

[shoobe01]

I always see Delrin, unless it's a bit further along and also subject to enough stress they use CuBe

Small run people tend to buy it from the scrap bin at the plastic distributor though. That helps on the cost a lot. Cheap enough I have some I have liberated from their shops and they don't care.

Wax, when I've seen it, is for CNC'd positives for casting. But seems to be the same thing, is called Machinable Wax, from and is AFAIK always from the very 1890s sounding Machinable Wax Company (okay, MachinableWax.com Inc, but close enough)
https://www.machinablewax.com/productlist.php

 

[Walt Krafft]

There are computer programs that will simulate your mills cutter path looking for crashes. You could also set your Z axis high and run your program. Move down a little at a time.

 

[rardoin]

The machinable wax is great. The edges/corners hold nice and sharp....no break-out. I rigged an air-gun and a solenoid valve controlled by an M code to turn on/off the air just like it would have been coolant (HAAS controller). The chips are easy to blow out of the way. I made several complex shaped molds with 3-d machining programs to fabricate prototype/one off carbon fiber race car parts. It worked great and the molds were durable enough to hold positioning pins during multiple uses. I had to use chemical catalyzed epoxy instead of thermo set prepreg but for my purposes it was fine.